Tennessee Republican Scott DesJarlais survived his primary in the 4th District Thursday night against former Mitt Romney aide Grant Starrett.

Starrett tweeted that he called DesJarlais to concede shortly before The Associated Press called the race in the congressman's favor. DesJarlais won 52 percent of the vote to Starrett's 43.

DesJarlais was rocked by scandal in 2012 when it came to light that the self-described pro-life congressman had previously encouraged an ex-wife and a mistress (who was also a patient) to have abortions.

The physician easily won the general election that year, but only narrowly survived his 2014 primary, winning a recount by just 38 votes.

Starrett, a 28-year-old lawyer moved to the district last year, ran an aggressive ground game, knocking on doors in places that DesJarlais' previous primary challenger had not.

He also made early personal investments in his campaign, which gave him a financial edge over DesJarlais. The three-term congressman has had trouble raising money since revelations of his abortion hypocrisy.

Starrett tried to run to the right of DesJarlais, a member of the House Freedom Caucus. He pledged to attack DesJarlais on policy issues, not personal matters. He went after DesJarlais for voting for legislation that included funding for food stamps, for example.

But Starrett's policy attacks on the life issue carried an implicit allusion to DesJarlais' past. In television ads and mail pieces, he attacked the incumbent for not defining when life begins and not questioning Planned Parenthood more strongly.

DesJarlais, who spent a week in Cleveland for the Republican National Convention two weeks ago, was one of Donald Trump's earliest congressional backers.

Even without much of a ground operation, in a low-turnout primary, he still earned support from party loyalists who may have accepted his pleas for forgiveness during the 2014 campaign when he was diagnosed with cancer.

DesJarlais used his longer-standing ties to the district to paint Starrett, a Stanford graduate, as an outsider. One mailer pictured Starrett in front of palm trees and labeled him "Mr. California."